Pen Color or Ink Color?

“Does the color of the pen I use matter?”

What the person asking means is the ink color, not the color of the pen. Is it completely wrong to say “pen color” instead of “ink color” (the question was asked during an English exam)?

"Pen color" or using "red pen" or "blue pen" should not be wrong when clearly indicating the color of the ink.

The Northwestern Examiner:

Education theory suggests grading with red pen causes stress for students.

Virginia Department of Environment Quality:

On your maps, draw arrows with a blue pen or highlighter to indicate...

Computer Science, Pricenton.edu:

Pen color. All geometric shapes (such as points, lines, and circles) are drawn using the current pen color. By default, it is black.